• Bulletin of the Korean Chemical Society
• /
• 제20권9호
• /
• pp.1010-1016
• /
• 1999

We synthesized the photoresponsive side chain polymers containing aminonitro azobenzene for studying the effect of temperature on photoinduced birefringence. Four different copolymers were prepared using methacrylate, α-methylstyrene, and itaconate monomer. Photoisomerization was observed under the exposure of UV light using UV-VIS absorption spectroscopy. Reorientation of polar azobenzene molecules induced optical anisotropy under a linearly polarized light at 532 nm. The change of the birefringence was observed with increasing the sample temperature under a continuous irradiation of excitation light. We could estimate the activation energy of molecular motion in thermal and photochemical mode. Besides the effect of glass transition temperature on the activation energy, we focused our interests on the effect of geometrical hindrance of polar azobenzene molecules and cooperative motion of environmental mesogenic molecules in the vicinity of polar azobenzene molecules.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
• /
• pp.121-122
• /
• 2003

In this study a microchannel with various arrangement of blocks is newly proposed. This design comprises periodically arranged simple blocks. In this configuration, the stirring is greatly enhanced at a certain geometric parameter set. To characterize the flow field and the stirring effect both the numerical and experimental methods were employed. To obtain the velocity field, three-dimensional numerical computation to the Navier Stokes equations are performed by using a commercial code, FLUENT 6.0. The fluid-flow solutions are then cast into studying the characteristics of stirring with the aid of Lyapunov exponent. The numerical results show that the particles' trajectories in the microchannel heavily depend on the block arrangement. It was shown that the stirring is significantly enhanced at larger block-height and it reaches maximum when the height is 0.8 times the channel width. We also studied the effect of the block stagger angle, and it turns out that the stirring performance is the best at the block angel ${45^\circ}$.

• 한국정보통신학회논문지
• /
• 제15권1호
• /
• pp.257-263
• /
• 2011

최근 증강현실(Augmented Reality)에 대한 관심이 증대되고, 이와 관련된 기술들이 발전함에 따라서 증강현실이 다양한 분야에 적용하려는 시도가 늘어나고 이에 대한 활용에도 기대가 모아지고 있다. 본 논문에서는 높은 해상도의 모델파일을 지원하고 보다 높은 증강현실을 위한 기술지원을 하는 Goblin XNA 기반으로 시스템을 구현하였다. 마커의 개수, 위치 및 카메라와의 거리 변화에 따른 모델 출력의 관계를 실험을 통해서 확인하였으며, 이를 바탕으로 유아용 학습 콘텐츠를 제작하고 구현하였다. 구현한 콘텐츠에서 각 페이지에 있는 마커에 유아에게 친숙한 캐릭터를 띄우므로 집중력을 높임과 동시에 학습보조자가 원활하게 콘텐츠를 사용할 수 있도록 하였다. 또한 콘텐츠의 페이지마다 3개의 마커를 두어 일부분이 장애물에 의해 가려지더라도 원활한 인식을 할 수 있도록 하였다. 그리고 내용에 맞게 3D 모델이 증강되는 동시에 사운드가 재생되도록 하여 학습에서의 현존감과 몰입을 높여 학습효과를 극대화하도록 하였다.

• 한국산학기술학회논문지
• /
• 제12권4호
• /
• pp.1609-1620
• /
• 2011

본 연구의 목적은 독서토론 진로집단 상담프로그램이 초등학생의 진로발달과 성취동기의 향상에 영향을 미치는지 그 효과를 알아보는데 있다. 이를 위하여 초등학생 5학년 세 학급을 실험집단, 비교집단 A, 비교집단 B로 각각 선정하였다. 실험집단에는 독서토론 진로집단 상담프로그램을 5주간 10회기에 걸쳐 실시하였고, 같은 기간 비교집단 A는 진로인식 집단상담 프로그램을, 비교집단 B는 교과학습을 실시하였다. 연구결과 독서토론 진로상담 프로그램 집단이 교과학습을 실시한 집단에 비해 진로발달에 유의한 향상이 있었으나 진로인식 상담 집단에 비해서는 유의한 차이점이 나타나지 않았다. 또한 독서토론 진로상담 프로그램 집단이 교과학습을 실시한 집단과 진로인식 상담 집단에 비해 성취동기가 유의하게 향상되었다.

• 한국환경과학회지
• /
• 제20권7호
• /
• pp.819-828
• /
• 2011

This research was done to clarify the cooling effect of water particles generated from a fountain. This effect is a one way to control the heat island effect of big cities. The result of this research was drawn by setting the jets of water in a certain height, and then studying the diffusion of water particles, which is affected by the size of the particles and the wind speed, and the cooling effect caused by the diffusion. 1) When a diameter of a water drop was 500 ${\mu}m$ and the wind speed was 2.0 to 6.0 m/sec, the water drop diffused 75 to 190m, and the water vapor spread over 175 to 440 m. As a result, there was more than $0.5^{\circ}C$ of cooling effect on the temperature in the atmosphere 130 to 330m around the water fountain. 2) When a diameter of a water drop was 750 ${\mu}m$ and the wind speed was 2.0 to 6.0 m/sec, the water drop diffused 65 to 150 m, and the water vapor spread over 160 to 405 m. Moreover, there was more than $0.5^{\circ}C$ of cooling effect on the temperature in the atmosphere 110 to 275 m around the water fountain. 3) After studying on the relationship between the diameter of water drop and the wind speed, and the diffusion of water particles and the range of the atmosphere that was cooled, a result could be drawn from the research that the smaller the diameter of the water vapor gets and the faster the wind speed becomes, the wider the water particles diffuse and the cooler the atmosphere around the fountain becomes. 4) This research further extrapolates that when the ordinary water(tap water, water from river and stream) is used in a fountain, the cooling effect of the air near the fountain can be approached similarly. If the seawater is used in a fountain, there is to be more to concern not only on cooling effect on the air, but also on other effects on surrounding environment generated by the salt in seawater.

• 가족자원경영과 정책
• /
• 제20권4호
• /
• pp.35-47
• /
• 2016

This research aimed to observe adolescent children's use of time and to discover the parent-related factors that affect adolescent children's use of time. The subjects included 2,092 fourth-grade elementary school students and 2,108 first-grade middle school students. We used data from the Korean Children and Youth Panel Survey. We tested sociodemographic factors, parents characteristics, and time usage, and we studied these factors using SPSS version 23.0; the results are as follows. Firstly, in the subordinate scope of the child-rearing attitude of parents, affection fourth-grade elementary school students(M = 1.83) and first-grade middle school students(M = 2.02). Inconsistency had an effect on fourth-grade elementary school students(M = 1.99), and first-grade middle school students(M = 2.12). Excessive expectations had an effect on fourth-grade elementary school students(M = 2.40) and first-grade middle school students(M = 2.55). Over-involvement had an effect on fourth-grade elementary school students(M = 2.68)and first-grade middle school students(M = 2.80). Finally, giving reasonable explanations had an effect on fourth-grade elementary school students(M = 1.51)and first-grade middle school students(M = 1.68). Secondly, in fourth-grade elementary school students(M = 463.35) and first-grade middle school students(M = 378.75). Further, studying hours during weekdays had an effect on fourth-grade elementary school students(M = 456.15) and first-grade middle school students(M = 460.86). Free activity hours during had an effect on fourth-grade elementary school students(M = 390.54) and first-grade middle school students(M = 387.11). Sleeping hours during holidays had an effect on fourth-grade elementary school students(M = 544.85) and first-grade middle school students (M = 511.74). Studying hours during holidays had an effect on fourth-grade elementary school students (M = 484.86) and first-grade middle school students (M = 511.74). Free activity hours during holidays had an effect on fourth-grade elementary school students(M = 518.68) and first-grade middle school students(M = 509.73). Thirdly, by observing the relative influence of related factors on adolescent children's use of time, grade(${\beta}$ = -.284), gender(${\beta}$ = -.208), over-involvement(${\beta}$ = -.380), supervising(${\beta}$ = -.217), and (${\beta}$ = .243) in terms of the child-rearing attitudes of parents was found to affect study hours($F=2.595^{**}$). The education level of fathers(${\beta}$ = -.144) results in(${\beta}$ = 1.991) and longer free activity hours for children($F= 4.116^{***}$). This research can be used to study the influence of parents'child-rearing attitudes on adolescent children's use of time and to suggest the role of parents in adolescents' ability to manage time effectively using practical.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1999년도 제29회 춘계학술대회
• /
• pp.73-79
• /
• 1999

Finite element equations by using fast Fourier transformation were formulated for studying temperatures resulting from frictional heating in sliding systems. The equations include the effect of velocity of moving components. The program developed by using FFT-FEM that combines Fourier transform techniques and the finite element method, was applied to the sliding bearing system. Numerical prediction obtained by FFT-FEM was in an excellent agreement of experimental temperature measurements.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.392-393
• /
• 2009

The study is aimed at studying a weakly relativistic oversized BWO with a Bragg reflector entrance of SWS. The Bragg reflector reflects microwaves, while it is open for beam propagations. By changing the boundary condition at the beam entrance, the effect of the Bragg reflector on the BWO performance is examined.

• Communications for Statistical Applications and Methods
• /
• 제4권1호
• /
• pp.119-128
• /
• 1997

Added variable plot and component-plus-residual plot are very useful for studying the role of a predictor in classical regression analysis. The former is usually used to check the effect of adding a new variable to existing model. The latter has been suggested as computationally convenient substitutes for the added variable plots, however, this plot is found to be better in detecting nonlinear relationships of a new predictor. By combining these two plots dynamically, we can take advantages of two plots simultaneously. And even further, we can get some knowledge of collinearity between a new predictor and predictors already in the model, and more accurate information about the possible outliers.

• Journal of the Korean Statistical Society
• /
• 제4권2호
• /
• pp.139-151
• /
• 1975

Individual effect of genes controlling quantitative traits can not ordinarily be distinguised from one another. Consequently, it is not possible to determine the mode of inheritance for single genes. By studying their combined effectsin segregating generations, however, one can gain some insight into their behavior and can make statistical inferences about their average gene action. The investigation reported herein was to extend genetic variance components and variance and covariance analyses, special attention was given to the genetic statistics from which least square estimators of genetic parameters are obtained.